1 Field of the Invention
The field of the present invention is a system for detecting the abnormality of a steering angle sensor which is mounted in a vehicle to detect the steering angle of a steering wheel of the vehicle.
2 Description of the Prior Art
There are conventionally known such systems which are designed so that the steering angle is judged to be abnormal, if the steering angle is not varied more than a predetermined value during travelling of a vehicle, as disclosed in Japanese Patent Application Laid-open No. 200423/86.
In the above prior art system, however, the abnormality is necessarily not detected reliably, because the steering angle may be maintained constant in some cases during travelling of the vehicle. In addition, even if a timer is used to judge the continuation of the constant steering angle in order to ensure the judgement of the abnormality, the detection of the abnormality may be delayed by setting of such duration.